US uses lasers to achieve fusion energy gain for second time

Using a 192-beam laser at Lawrence Livermore National Laboratory's National Ignition Facility, researchers heated and compressed hydrogen atoms, exceeding solar temperatures.
Ameya Paleja
NIF preamplifier support structure at the National Ignition Lab at LLNL.
NIF preamplifier support structure at the National Ignition Lab at LLNL.

Lawrence Livermore National Laboratory 

Researchers at the Lawrence Livermore National Laboratory (LLNL) in California have successfully repeated the breakthrough experiment in nuclear fusion performed in December last year, Reuters reported.

The experiment performed on July 30 had a higher yield than what was obtained in December, a spokesperson said.

Nuclear fusion presents an alternative means of satisfying Earth's energy requirements by mimicking stellar processes. As the world looks for ways to move away from fossil fuels, nuclear power is poised to make a comeback as an alternative. Given the checkered past of nuclear fission, scientists are enthusiastic about harnessing energy through nuclear fusion instead.

The technique entails colliding nuclei of lighter elements such as hydrogen to form relatively more massive elements like helium, resulting in the significant release of energy as a side effect. Such reactions do not occur at room temperature and large amounts of energy are required to create conditions conducive to generating fusion-powered energy.

The milestone was first achieved in December

For the method to be economically feasible, the procedure must yield more energy as an outcome than the initial input required to initiate the reaction – a milestone achieved by researchers for the first time last December.

Researchers at the National Ignition Facility (NIF) at the LLNL used a 192-beam laser to heat and compress hydrogen atoms to temperatures higher than that of the Sun. A total of 2.05 megajoules was used to power the lasers and an output of 3.15 megajoules was obtained.

As previously covered by Interesting Engineering, during that period, the energy disparity was sufficient only to boil a couple of kettles of water. Nonetheless, it marked a significant milestone, as it represented the first instance of the nuclear fusion method achieving a net energy gain.

US uses lasers to achieve fusion energy gain for second time
The target chamber of LLNL’s National Ignition Facility

Repeating the experiment

Just like any scientific accomplishment, researchers must establish that the initial success was not merely a fortunate incident. Therefore, the team convened once more to reproduce the procedure in July of this year.

While data from the experiment is still being analyzed, a spokesperson confirmed that the experiment was aiming for a higher energy yield. According to the webpage of the UK Atomic Energy Authority, a little over two pounds (one kilogram) of fusion fuel is capable of generating energy equivalent to 22 million pounds (10 million kilograms) of fossil fuels. Additionally, the process does not release carbon into the atmosphere.

This is the reason for ample excitement around developments in nuclear fusion space. Despite our significant technological progress, it has taken us over seven decades to arrive at this juncture, where we can finally attain a surplus of energy from a fusion reaction. This, though, is still far from being a practical energy solution that can be commercialized.

Many companies are involved in the race to tap into fusion energy, with one even achieving the Cherenkov radiation, an eerie blue glow, associated with nuclear fission, in a fusion reaction for the first time.